我目前正在try 安装libpq dev来安装psycopg2.问题是，当我try 安装它时，出现了一个错误，说我没有最新的libpq5版本.然而，当我试图下载更新版本的libpq5时，系统说我已经有了最新版本.错误的一个例子.
lhmendes@lhmendes-GA-78LMT-S2P:~$ sudo apt-get install libpq-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libpq-dev : Depends: libpq5 (= 12.4-0ubuntu0.20.04.1) but 12.4-1.pgdg20.04+1 is to be installed
E: Unable to correct problems, you have held broken packages.
lhmendes@lhmendes-GA-78LMT-S2P:~$ sudo apt-get install libpq5
Reading package lists... Done
Building dependency tree
Reading state information... Done
libpq5 is already the newest version (12.4-1.pgdg20.04+1).
0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.